Spiropyran‐Containing PDMS Coatings for Self‐Cleaning, UV Shielding, and Tunable Transparency

Glass surfaces commonly exhibited contamination, limited UV protection, and excessive solar transmission, which restrict their performance in advanced applications. Developing multifunctional coatings that integrate self‐cleaning, UV shielding, and tunable optical properties remains challenging, particularly through a scalable and fluorine‐free approach. Herein, we report a smart slippery coating based on a spiropyran‐functionalized PDMS/silicone oil matrix, fabricated via a simple one step spray coating method. The coatings exhibited high transmittance (> 81%) and UV shielding efficiency (61.19%). Upon irradiation, reversible spiropyran to merocyanine isomerization enables dynamic modulation of visible light transmittance, resulting in a 20.06% reduction in luminous transmittance. The coatings demonstrated notable chemical, mechanical, and UV durability, maintaining stable wettability performance under harsh environmental conditions. The low surface free energy (28.93 mJ m −2 ) of the coatings promoted effective self‐cleaning against various contaminants. These findings demonstrate a scalable and fluorine‐free method for fabricating photoresponsive coatings that self‐regulate light transmission without external energy input, highlighting their strong potential for smart‐window applications.